72167-83-0Relevant academic research and scientific papers
Efficient synthesis of 4-sulfanylcoumarins from 3-bromo-coumarins: Via a highly selective DABCO-mediated one-pot thia-Michael addition/elimination process
Mostardeiro, Vitor B.,Dilelio, Marina C.,Kaufman, Teodoro S.,Silveira, Claudio C.
, p. 482 - 491 (2020/01/13)
A facile and efficient protocol for the highly selective direct sulfanylation of 3-bromocoumarins under DABCO promotion, was developed. The transformation took place with aromatic and aliphatic thiols as well as with α,ω-dithiols, affording the expected products in very good to excellent yields. Simple and convenient ways to access 4-((ω-mercaptoalkyl) thio)coumarins and the dimeric 4,4′-(alkane-1,4-diylbis(sulfanediyl))bis(coumarins) were also devised with the use of α,ω-alkanedithiols in different ratios with regards to the starting 3-bromocoumarin. The transformation seems to proceed through the DABCO-mediated thia-Michael stereoselective addition of the thiolate anion to the α,β-unsaturated carbonyl system of the coumarin, followed by a DABCO-assisted stereoselective dehydrobromination of the resulting α-bromo carbonyl intermediate.
Palladium-Catalyzed Synthesis of Benzothiophenes via Cross-Dehydrogenative Coupling of 4-Arylthiocoumarins and Pyrones
Zhang, Jin,Zhuang, Yuyu,Ma, Yangmin,Yang, Xiufang,Szostak, Michal
, p. 5709 - 5714 (2019/11/21)
Benzothiophenes represent a pivotal class of sulfur heterocycles and their synthesis has attracted significant attention to generate bioactive scaffolds. Herein, we report a convergent, atom- and step-economic method for the synthesis benzothiophenes by cross-dehydrogenative coupling (CDC) of 4-arylthiocoumarins in good to excellent yields. We further demonstrate cross-dehydrogenative coupling of 4-arylthio-2-pyrones to afford alternative substitution of benzothiophenes. The presence of a labile ester carbonyl moiety provides functional handle for further functionalization by coumarin deconstruction. Most crucially, the manuscript demonstrates that the use of readily accessible templated synthesis has a significant potential for the rapid assembly of sulfur heterocycles by dehydrogenative coupling mechanism.
Direct sulfanylation of 4-hydroxycoumarins with thiols in water
Peng, Yi-Yuan,Wen, Yanfang,Mao, Xuechun,Qiu, Guanyinsheng
experimental part, p. 2405 - 2406 (2009/07/26)
The direct sulfanylation of 4-hydroxycoumarins with thiols via C-OH bond activation in water under mild conditions is described, which afforded the corresponding 4-sulfanylcoumarins in good yields.
